scholarly journals Chytridiomycosis-induced mortality in a threatened anuran

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241119
Author(s):  
Andrea J. Adams ◽  
Allan Pessier ◽  
Peggy Cranston ◽  
Robert L. Grasso
Keyword(s):  
Sierra Nevada ◽  
Batrachochytrium Dendrobatidis ◽  
Disease Risk ◽  
Amphibian Declines ◽  
Ex Situ ◽  
Source Population ◽  
Sierra Nevada Mountains ◽  
Selection For ◽  
Source Populations ◽  
Two Populations

Effectively planning conservation introductions involves assessing the suitability of both donor and recipient populations, including the landscape of disease risk. Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), has caused extensive amphibian declines globally and may hamper reintroduction attempts. To determine Bd dynamics in potential source populations for conservation translocations of the threatened California red-legged frog (Rana draytonii) to Yosemite National Park, we conducted Bd sampling in two populations in the foothills of the Sierra Nevada Mountains, California, U.S.A. At one of two sites, we observed lethally high Bd loads in early post-metamorphic life stages and confirmed one chytridiomycosis-induced mortality, the first such report for this species. These results informed source population site selection for subsequent R. draytonii conservation translocations. Conservation efforts aimed at establishing new populations of R. draytonii in a landscape where Bd is ubiquitous can benefit from an improved understanding of risk through disease monitoring and ex situ infection studies.

scholarly journals A pesticide paradox: Fungicides indirectly increase fungal infections

2017 ◽  
Author(s):  
Jason R. Rohr ◽  
Jenise Browna ◽  
William A. Battaglin ◽  
Taegan A. McMahon ◽  
Rick A. Relyea
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Crop Yields ◽  
Insect Pests ◽  
Disease Risk ◽  
Fungal Infections ◽  
Pathogenic Fungus ◽  
Pathogen Resistance ◽  
Amphibian Declines ◽  
Unintended Consequences ◽  
Tree Frog

AbstractThere are many examples where the use of chemicals have had profound unintended consequences, such as fertilizers reducing crop yields (paradox of enrichment) and insecticides increasing insect pests (by reducing natural biocontrol). Recently, the application of agrochemicals, such as agricultural disinfectants and fungicides, has been explored as an approach to curb the pathogenic fungus, Batrachochytrium dendrobatidis (Bd), which is associated with worldwide amphibian declines. However, the long-term, net effects of early-life exposure to these chemicals on amphibian disease risk have not been thoroughly investigated. Using a combination of laboratory experiments and analysis of data from the literature, we explored the effects of fungicide exposure on Bd infections in two frog species. Extremely low concentrations of the fungicides azoxystrobin, chlorothalonil, and mancozeb were directly toxic to Bd in culture. However, estimated environmental concentrations of the fungicides did not reduce Bd on Cuban tree frog (Osteopilus septentrionalis) tadpoles exposed simultaneously to any of these fungicides and Bd, and fungicide exposure actually increased Bd-induced mortality. Additionally, exposure to any of these fungicides as tadpoles resulted in higher Bd abundance and greater Bd-induced mortality when challenged with Bd post-metamorphosis, an average of 71 days after their last fungicide exposure. Analysis of data from the literature revealed that previous exposure to the fungicide itraconazole, which is commonly used to clear Bd infections, made the critically endangered booroolong frog (Litoria booroolongensis) more susceptible to Bd. Finally, a field survey revealed that Bd prevalence was positively associated with concentrations of fungicides in ponds. Although fungicides show promise for controlling Bd, these results suggest that, if fungicides do not completely eliminate Bd or if Bd re-colonizes, exposure to fungicides has the potential to do more harm than good. To ensure that fungicide applications have the intended consequence of curbing amphibian declines, researchers must identify which fungicides do not compromise the pathogen resistance mechanisms of amphibians.

scholarly journals Breeding Centers, Private Ranches, and Genomics for Creating Sustainable Wildlife Populations

BioScience ◽  
2019 ◽  
Vol 69 (11) ◽  
pp. 928-943 ◽  
Author(s):  
David Wildt ◽  
Philip Miller ◽  
Klaus-Peter Koepfli ◽  
Budhan Pukazhenthi ◽  
Katy Palfrey ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Ex Situ ◽  
Source Population ◽  
Public And Private ◽  
Species Survival ◽  
Source Populations ◽  
Public And Private Sector ◽  
Induced Changes ◽  
Species Declines

Abstract Human-induced changes to environments are causing species declines. Beyond preserving habitat (in situ), insurance (ex situ) populations are essential to prevent species extinctions. The Conservation Centers for Species Survival (C2S2) is leveraging space of breeding centers and private ranches to produce “source populations”—genetically diverse reservoirs that also support research and reintroductions. The initial focus is on four African antelopes. C2S2 has developed a program, the Source Population Alliance, that emphasizes animals living in spacious, naturalistic conditions in greater numbers than can be accommodated by urban zoos. Simulation modeling demonstrates how herds can rapidly increase population abundance and retain genetic diversity. Advances in genomics and resulting DNA data allow monitoring of genetic diversity and parentage as well as refined decision-making. This approach, neither pure in situ nor ex situ, but rather “sorta situ”, is an innovative way of linking public and private sector resources to ensure that endangered species survive.

scholarly journals Erosion rates as a potential bottom‐up control of forest structural characteristics in the Sierra Nevada Mountains

Ecology ◽  
2015 ◽  
Vol 96 (1) ◽  
pp. 31-38 ◽  
Author(s):  
David T. Milodowski ◽  
Simon M. Mudd ◽  
Edward T. A. Mitchard
Keyword(s):  
Sierra Nevada ◽  
Structural Characteristics ◽  
Bottom Up ◽  
Erosion Rates ◽  
Sierra Nevada Mountains

Investigation of 18 physiologically dormant Australian native species: germination response, environmental correlations and the implications for conservation

2020 ◽  
pp. 1-9
Author(s):  
Justin C. Collette ◽  
Mark K.J. Ooi
Keyword(s):  
Native Species ◽  
Strong Dependence ◽  
Ex Situ ◽  
Source Population ◽  
Seasonal Temperature ◽  
Environmental Correlations ◽  
Rainfall Season ◽  
Germination Response ◽  
Rainfall Seasonality ◽  
Germination Experiments

Abstract For physiologically dormant (PD) species in fire-prone environments, dormancy can be both complex due to the interaction between fire and seasonal cues, and extremely deep due to long intervals between recruitment events. Due to this complexity, there are knowledge gaps particularly surrounding the dormancy depth and cues of long-lived perennial PD species. This can be problematic for both in situ and ex situ species management. We used germination experiments that tested seasonal temperature, smoke, dark and heat for 18 PD shrub species distributed across temperate fire-prone Australia and assessed how germination was correlated with environmental factors associated with their home environments. We found extremely high levels of dormancy, with only eight species germinating above 10% and three species producing no germination at all. Seven of these eight species had quite specific seasonal temperature requirements and/or very strong responses to smoke cues. The maximum germination for each species was positively correlated with the mean temperature of the source population but negatively correlated with rainfall seasonality and driest months. The strong dependence on a smoke cue for some of the study species, along with examples from other studies, provides evidence that an obligate smoke response could be a fire-adapted germination cue. Germination response correlated with rainfall season of the source populations is a pattern which has often been assumed but little comparative data across sites with different rainfall seasonality exists. Further investigation of a broader range of species from different rainfall season environments would help to elucidate this knowledge gap.

scholarly journals Detection of drought‐induced blue oak mortality in the Sierra Nevada Mountains, California

Ecosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Margarita Huesca ◽  
Susan L. Ustin ◽  
Kristen D. Shapiro ◽  
Ryan Boynton ◽  
James H. Thorne
Keyword(s):  
Sierra Nevada ◽  
Blue Oak ◽  
Sierra Nevada Mountains ◽  
Oak Mortality

Drought year changes in streambank profiles on incised streams in the Sierra Nevada Mountains

Geomorphology ◽  
1996 ◽  
Vol 15 (1) ◽  
pp. 47-56 ◽  
Author(s):  
K. Lynn Zong ◽  
Sherman Swanson ◽  
Tom Myers
Keyword(s):  
Sierra Nevada ◽  
Sierra Nevada Mountains

Value Messages Collide with Reality: Joseph Kurihara and the Power of Informal Education

2010 ◽  
Vol 50 (1) ◽  
pp. 1-33 ◽  
Author(s):  
Eileen H. Tamura
Keyword(s):  
Sierra Nevada ◽  
Informal Education ◽  
Eastern Slope ◽  
Sierra Nevada Mountains ◽  
Oil Tank

On a cool, crisp winter afternoon in a California desert, at the foot of the eastern slope of the Sierra Nevada Mountains, a crowd of more than two thousand people gathered. Some were curious; more were angry. Before all of them, standing on an oil tank with a microphone and loudspeaker, forty-seven-year-old Joseph Y. Kurihara shouted angry words of defiance. Referring to the generally despised Fred Tayama, who was assaulted the night before, Kurihara bellowed, “Why permit that sneak to pollute the air we breathe? … Let's kill him and feed him to the roving coyotes! … If the Administration refuses to listen to our demand, let us proceed with him and exterminate all other informers in this camp.”

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